EV Digest 6926
Topics covered in this issue include:
1) RE: Rolling Resistance - how to measure
by "Phil Marino" <[EMAIL PROTECTED]>
2) Slightly OT: Painting your EV for less than $100
by "Brian Pikkula" <[EMAIL PROTECTED]>
3) RE: Motor cooling and temps
by "damon henry" <[EMAIL PROTECTED]>
4) RE: Slightly OT: Painting your EV for less than $100
by "damon henry" <[EMAIL PROTECTED]>
5) Re: Motor cooling and temps
by "Mark Eidson" <[EMAIL PROTECTED]>
6) Re: Motor cooling and temps
by Jeff Major <[EMAIL PROTECTED]>
7) Re: Wire 4/0
by "Harry Houck" <[EMAIL PROTECTED]>
8) Re: Rolling Resistance - how to measure
by john fisher <[EMAIL PROTECTED]>
9) RE: 55mph - calculating HP
by "Phil Marino" <[EMAIL PROTECTED]>
10) Re: Slightly OT: Painting your EV for less than $100
by Steve Peterson <[EMAIL PROTECTED]>
11) Re: Cheap
by Marcin Ciosek <[EMAIL PROTECTED]>
12) Re: Slightly OT: Painting your EV for less than $100
by "james s" <[EMAIL PROTECTED]>
13) Re: Google presses for 100 MPG vehicle
by M Bianchi <[EMAIL PROTECTED]>
14) Re: Slightly OT: Painting your EV for less than $100
by Ralph Merwin <[EMAIL PROTECTED]>
15) Re: Google presses for 100 MPG vehicle
by "TrotFox Greyfoot" <[EMAIL PROTECTED]>
16) RE: 55mph - calculating HP
by "Dewey, Jody R ATC COMNAVAIRLANT, N422G5G" <[EMAIL PROTECTED]>
17) RE: Slightly OT: Painting your EV for less than $100
by "Dewey, Jody R ATC COMNAVAIRLANT, N422G5G" <[EMAIL PROTECTED]>
18) Brush timing (was: Zombie rises from the dead Siamese8 lives
again)
by Bill Dube <[EMAIL PROTECTED]>
19) Re: Cheap
by Lee Hart <[EMAIL PROTECTED]>
20) Re: 55mph - calculating HP
by "Peter Gabrielsson" <[EMAIL PROTECTED]>
--- Begin Message ---
From: "Rob Hogenmiller" <[EMAIL PROTECTED]>
Reply-To: ev@listproc.sjsu.edu
To: "EV Discussion" <ev@listproc.sjsu.edu>
Subject: Rolling Resistance
Date: Thu, 21 Jun 2007 08:30:04 -0500
This morning I did a test for rolling resistance.
I was traveling at 60mph on flat ground in my car on a non windy day.
It took me 7 seconds to slow 0.1 Miles (on the odometer)
My speed at the distance of 0.1 Miles was 55mph at the 7second mark.
What would be my rolling resistance in this range 55-60mph?
God bless
Rob -
Because of the wind drag at highway speeds, you can't deduce rolling
resistance very well from this particular test. The wind drag would swamp
the tire drag.
But, it could work very well if you do it at slower speeds. You might try
timing the car from , for example, 15 MPH to 5 MPH. A those speeds, the air
drag is fairly small and won't drastically affect your resutls.
Make sure the car is out of gear, and the road is VERY level. Doing the
same test in both directions - and averaging the results - would help
account for any slight grade of the road.
Here is how you would do the calculation:
1. Calculate your decelleration:
First, convert your speeds to FPS ( feet/second ) by multiplying by 1.47.
For example, 15 MPH is 22 FPS, and 5 MPH is 7.35 FPS.
Now, divide the change in speed by the slow-down time to get decelleration
in feet per second squared:
( let's use 40 seconds as an example)
Decelleration = (22 FPS - 7.35 FPS) / 40 S = 0.367 feet/sec/sec
2. To get the RR factor, divide this decelleration by the acceleration of
gravity **( 32.2 FPS):
RR = 0.367/ 32.2 = 0.011 = 1.1 %
So, in this case your calculated rolling resistance coefficient would be 1.1
%.
The difficult part might be to determine exactly when you reach the final
speed.
Or, you could use 0 MPH ( dead stop) as your final speed - the calculation
is even simpler.
Good luck. Let us know what you measure ( and what tires and tire pressure
you are using)
Phil Marino
** Rolling resistance is the ratio of drag to car weight. By taking the
ratio of decelleration ( proportional to tire drag) to the acceleration of
gravity ( proportional to car weight) you get the same value.
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--- Begin Message ---
Since the majority of our EVs are > 10 years old, the paint on them
isn't like it used to be. However, I have a hard time justifying
spending $2k for something that will not propel my EV.
I have some time on my hands while saving up for my next big purchase
( a 9" ADC), so I am considering painting the car myself using a
roller. The kicker is that it costs < $100 to do it (not including
the random orbit polisher). I'll also be able to bondo the dents,
too. There are several sites that explain this and show their
results. Has anyone tried this before? Results?
http://rollyourcar.com/default.aspx
http://carpainting.wetpaint.com/page/Rollering+Interlux+Brightside+Polyurethane+Paint?t=anon
The original thread that introduced the roll on method to the masses:
(30+ pages)
http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Number=2331682&page=0&fpart=1&vc=1%3Cbr%20/%3E
Thanks,
Brian
http://www.austinev.org/evalbum/960
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Your motor has an internal fan, so spinning the motor does help keep it
cool. You just need to realize that even without power applied you can spin
your motor too fast and destroy it. This will not be a problem unless you
down shift, or pick up significant speed coasting down a hill.
The easiest way to add external cooling is to modify or replace the brush
guard so that it has an inlet for forcing air through the motor.
damon
From: "Richard Acuti" <[EMAIL PROTECTED]>
Reply-To: ev@listproc.sjsu.edu
To: ev@listproc.sjsu.edu
Subject: Motor cooling and temps
Date: Thu, 21 Jun 2007 09:49:26 -0400
Well here's the good news:
I drove my car home 20 miles on the freeway at 55 & 65 mph. The moment I
got home, I slapped my multi-meter on the temp probe pigtails of my motor
to see if the probe was open or closed (since I haven't hooked up a
dummy/warning light yet) and the probe was still open. I assume this is
good and that I haven't overheated.
The motor is an ADC L91-4003 6.7" motor. I've seen motors that have a
coupling on the body where you can hook up a duct or a cooling blower.
These motors have no such fitting. This leaves me with more questions:
How can I set up forced air cooling for this motor?
Am I supposed to?
Do ADC motors provide some self cooling while they spin? For instance, if I
leave the car in gear while I coast, is the motor circulating air?
Should I just mount a couple of small DC fans to blow on the motor body?
Rich
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Personally, I am spending the money and having a professional do mine.
Regardless of the method there are some basics to painting that always
remain true. The first is that the key to any good paint job is in the
prep. If you get everything straight and clean, and you use the correct
primers and paint for the job at hand you will have a better chance at a
successful job. The second is that light colors are more forgiving of
mistakes than dark colors. If you don't really know what you are doing, or
you do not have a very detail oriented personallity, then use a lighter
color and your shortcomings won't be nearly as noticable.
damon
From: "Brian Pikkula" <[EMAIL PROTECTED]>
Reply-To: ev@listproc.sjsu.edu
To: ev@listproc.sjsu.edu
Subject: Slightly OT: Painting your EV for less than $100
Date: Thu, 21 Jun 2007 10:32:25 -0500
Since the majority of our EVs are > 10 years old, the paint on them
isn't like it used to be. However, I have a hard time justifying
spending $2k for something that will not propel my EV.
I have some time on my hands while saving up for my next big purchase
( a 9" ADC), so I am considering painting the car myself using a
roller. The kicker is that it costs < $100 to do it (not including
the random orbit polisher). I'll also be able to bondo the dents,
too. There are several sites that explain this and show their
results. Has anyone tried this before? Results?
http://rollyourcar.com/default.aspx
http://carpainting.wetpaint.com/page/Rollering+Interlux+Brightside+Polyurethane+Paint?t=anon
The original thread that introduced the roll on method to the masses:
(30+ pages)
http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Number=2331682&page=0&fpart=1&vc=1%3Cbr%20/%3E
Thanks,
Brian
http://www.austinev.org/evalbum/960
_________________________________________________________________
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--- End Message ---
--- Begin Message ---
The drawing for this motor calls out "Ventilated Motor with Fan".
This motor has an internal fan/impeller on the drive end that sucks
air thru from the brush end. You can feel the air blowing out around
the whole motor when it is running. If the motor is turning the
impeller is sucking air thru the motor. me
On 6/21/07, Richard Acuti <[EMAIL PROTECTED]> wrote:
Well here's the good news:
I drove my car home 20 miles on the freeway at 55 & 65 mph. The moment I got
home, I slapped my multi-meter on the temp probe pigtails of my motor to see
if the probe was open or closed (since I haven't hooked up a dummy/warning
light yet) and the probe was still open. I assume this is good and that I
haven't overheated.
The motor is an ADC L91-4003 6.7" motor. I've seen motors that have a
coupling on the body where you can hook up a duct or a cooling blower. These
motors have no such fitting. This leaves me with more questions:
How can I set up forced air cooling for this motor?
Am I supposed to?
Do ADC motors provide some self cooling while they spin? For instance, if I
leave the car in gear while I coast, is the motor circulating air?
Should I just mount a couple of small DC fans to blow on the motor body?
Rich
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Hi Richard,
Motors come in a lot of ventilation configurations. I
do not know what your's looks like. Some are
ventilated with internal fan. There would be slots in
the drive end head (DEH) where it attaches to the
frame. Then a fan is attached to the shaft next to
the armature opposite the commutator. This radial fan
blows air out of the DEH slots while sucking it in
thru the slots in the commutator end head(CEH). The
cool air comes in around the brushes and comm, is
pulled thru the frame between the field coils and
somewhat across the armature , then out. The shaft
mounted internal fan is not too efficient, very
ineffective at low speeds, and does nothing at
standstill, where you can get a significant heat soak
in the motor if you come to a stop after a hard pull.
Some motors are ventilated without fan. Slots at one
end or both. The armature is not a smooth surface, so
it will mix the air up and provide some exchange with
outside. Not as effective as with the fan.
Then there are totally enclosed motors. These can
have a fan inside, but most do not. Some totally
enclosed motors have a fan outside attached to the
shaft with a shroud to blow air over the frame, mostly
AC motors.
So, to get back to your motor. Does it have slots on
the end heads? An internal fan? I have always been a
fan (no pun intended) of forced ventilation for EV
motors. That is using an external separately driven
fan to blow air thru the motor. This provides a
steady stream of cool, clean air over the heat
producing components in the motor at all speeds, even
stopped. Air should be ducted from a clean intake,
perhaps thru a filter. This should enter the CEH and
exit the DEH. Roland has posted some details.
The external fan can be started with a thermo switch
or just the key switch. Forced ventilation can be
added to motors having and internal fan as well as
those without. You will need to have slots at both
ends.
Air cooling over the outside of the motor is not
nearly as effective, but will help.
And keeping the motor cooler will make it a little
more efficient, since the resistance of copper rises
with temperature, and also increase insulation life.
Hope this helps.
Jeff
--- Richard Acuti <[EMAIL PROTECTED]> wrote:
> Well here's the good news:
>
> I drove my car home 20 miles on the freeway at 55 &
> 65 mph. The moment I got
> home, I slapped my multi-meter on the temp probe
> pigtails of my motor to see
> if the probe was open or closed (since I haven't
> hooked up a dummy/warning
> light yet) and the probe was still open. I assume
> this is good and that I
> haven't overheated.
>
> The motor is an ADC L91-4003 6.7" motor. I've seen
> motors that have a
> coupling on the body where you can hook up a duct or
> a cooling blower. These
> motors have no such fitting. This leaves me with
> more questions:
>
> How can I set up forced air cooling for this motor?
> Am I supposed to?
> Do ADC motors provide some self cooling while they
> spin? For instance, if I
> leave the car in gear while I coast, is the motor
> circulating air?
> Should I just mount a couple of small DC fans to
> blow on the motor body?
>
> Rich
>
>
_________________________________________________________________
> PC Magazines 2007 editors choice for best Web
> mailaward-winning Windows
> Live Hotmail.
>
http://imagine-windowslive.com/hotmail/?locale=en-us&ocid=TXT_TAGHM_migration_HM_mini_pcmag_0507
>
>
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or just tow the car at a slow speed using a spring-scale to measure the
'weight' i.e. force
I'd do it in an empty parking lot, and have a driver in the towed car with brake
foot ready. ;>)
your odometer is so inaccurate its worthless IMO. Look into using a GPS or an accelerometer like a GTech. or a bicycle
speedo, after you measure actual wheel diameter.
I'd think, though, just spinning the wheels up on the lift would be good enough.
HTH
JF
Phil Marino wrote:
This morning I did a test for rolling resistance.
--- End Message ---
--- Begin Message ---
From: "Dewey, Jody R ATC COMNAVAIRLANT, N422G5G" <[EMAIL PROTECTED]>
Reply-To: ev@listproc.sjsu.edu
To: <ev@listproc.sjsu.edu>
Subject: RE: 55mph
Date: Thu, 21 Jun 2007 09:06:53 -0400
A lot of people don't have that kind of data though. I don't know the Cd
of my Nissan or the tire drag coefficient. I do however have the ability
to use that general calculation.
This reminds me of the story of the guy who was looking for his car keys
under a streetlight. A friend came along and asked him what he was doing
there. He said " I dropped my keys on the next block, but there's no
streetlight down there".
If you don't have the data for your car ( and don't want to try to find it
on the Web) then try this :
Use 0.01 for your tire RR, and use 0.35 for your drag coefficient. For the
frontal area, measure the car's height and width with a tape measure and
multiply them together, then multiply that number by 0.8. That will be a
good approximation. Then you can use the real formula.
You're much better off doing that than using the MOPAR "formula" - it really
makes no sense at all.
Phil Marino
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Phil Marino
Sent: Thursday, June 21, 2007 8:55
To: ev@listproc.sjsu.edu
Subject: RE: 55mph
Jody
This doesn't look like a useful formula to me. It might be close at a
particular speed (similar to a stopped watch being exactly correct twice a
day), but it would give you huge errors at most speeds.
It makes no account of frontal area, Cd, or tire drag coefficient,
Even worse, its says that the required horsepower it proportional to the
speed. Because air drag dominates at high speed, and the power it soaks up
is proportional to the cube of speed, this formula is way off.
For example, it would predict that your car would need twice the power to
travel at 60 MPH compared to 30 MPH. In most cases, you would need closer
to six times the power at double the speed.
If you know the frontal area, Cd, tire RR, and weight, Peter's calculations
should give you very accurate answers. if you don't know them, take your
best guess - and use it anyway.
It would still give you much better answers than the MOPAR version.
Phil
>From: "Dewey, Jody R ATC COMNAVAIRLANT, N422G5G" <[EMAIL PROTECTED]>
>Reply-To: ev@listproc.sjsu.edu
>To: <ev@listproc.sjsu.edu>
>Subject: RE: 55mph
>Date: Thu, 21 Jun 2007 08:29:37 -0400
>
>I got this off of a website for MOPARS:
>
>Engine horsepower required to sustain MPH on level ground (HPs):
>
>
> HPs =
> (MPH ÷ 3)
> + (WEIGHT ÷ 1,000 × MPH ÷ 10)
>
>
>Note: assumes engine HP must be 2 × the HP required at drive wheels.
>Example:
>What engine HP is required to sustain 75 MPH in a 3,600 pound vehicle?
>
>
>
> HPs =
> 75
> ÷ 3
> + (3,600 ÷ 1,000 × 75 ÷ 10)
> _____________________________
> 25
> + (3.6 × 7.5)
> _______________________________________
> 52 engine HP
>
>
>-----Original Message-----
>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
>Behalf Of Peter Gabrielsson
>Sent: Thursday, June 21, 2007 2:47
>To: ev@listproc.sjsu.edu
>Subject: Re: 55mph
>
>The forces you need to overcome are aerodynamic drag plus the rolling
>resistance. (This presumes level ground and no wind)
>
>The power required to overcome aerodynamic drag = 0.5rho*Cd*A*V*V*V
>where rho = density of air = 1.2 kg/m3, Cd = drag coefficient, A =
>frontal area of the car in m^2, V = velocity (55mph = 25m/s)
>
>For my fiat the numbers would be something like: P = 0.5 * 1.2 * 0.4 *
>0.6 * 25 * 25 * 25 => 2250W or about 3Hp
>
>The power required to overcome rolling resistance = V * Crr * g * m
>where V = velocity, Crr = coefficient of rolling resistance (0.006 -
>0.01 for lrr tires), g = gravitational constant (9.81m/s^2), m= mass
>of car in kg.
>
>So for a 1200kg (2500lbs) car with marginally low rolling resistance
>tires the power needed is 25*0.01*9.81*1200 => 3000W or about 4Hp
>
>Total power needed is thus 3+4 = 7Hp at the wheels. In real life you
>probably want twice as much at the motor. (due to wind, slopes &
>transmission losses)
>
>Someone check for mistakes, it's late ;)
>
>
>
>
>On 6/20/07, Rob Hogenmiller <[EMAIL PROTECTED]> wrote:
> > What is the mathematical formula to determine how much HP I will
> > need to maintain 55mph.
> >
> > For i.e.
> >
> > 5,000lbs vehicle x rolling resistance / 10HP= 50mph would eventually
> > produce given a long enough run.
> >
> > (I know that isn't anywhere close to the true formula ust trying to
> > get an
> > idea)
> >
> > God bless
> >
> >
> >
> >
>
>
>--
>www.electric-lemon.com
>
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--- Begin Message ---
Try:
http://www.electric-lemon.com/?q=node/174
--Steve
On Thu, 2007-06-21 at 10:32 -0500, Brian Pikkula wrote:
> Since the majority of our EVs are > 10 years old, the paint on them
> isn't like it used to be. However, I have a hard time justifying
> spending $2k for something that will not propel my EV.
>
> I have some time on my hands while saving up for my next big purchase
> ( a 9" ADC), so I am considering painting the car myself using a
> roller. The kicker is that it costs < $100 to do it (not including
> the random orbit polisher). I'll also be able to bondo the dents,
> too. There are several sites that explain this and show their
> results. Has anyone tried this before? Results?
>
> http://rollyourcar.com/default.aspx
>
> http://carpainting.wetpaint.com/page/Rollering+Interlux+Brightside+Polyurethane+Paint?t=anon
>
> The original thread that introduced the roll on method to the masses:
> (30+ pages)
> http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Number=2331682&page=0&fpart=1&vc=1%3Cbr%20/%3E
>
> Thanks,
> Brian
> http://www.austinev.org/evalbum/960
>
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Lee,
very good example. I like it.
I've been doing "passive" balancing in my BMS using connected in parallel on
each cell adjustable resistance and this was quite effective. Choosing proper
size of resistance and proper controlling algorithm you could try to balance
cells all the charging time.
Right now I've two different working active balancing solution and see at
least 10x faster balancing efficiency (and some additional benefits).
But controlling electronics and whole software is way too complicated to be
available for mass purpose. So discussed here zener+resistor circuit is
perfect for small apps.
Best regards,
Marcin
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You can usually get a discount from a body shop if you do all the prep
work as it's a large part of the job, you can also try and negotiate
cost for paint if they want to place an sticker on your car, you may
also have to have your car at their shop for an open house, just an
idea, or go for the rat rod look and paint the whole car flat black
with rattle cans.
--- End Message ---
--- Begin Message ---
Lee Hart: wrote ...
> > The A/C in many parts of the country is not a luxury. Here, A/C
> > is a necessity.
> :
> Use a timer to start the A/C a little while before you return to drive
> the car, so it can be far smaller.
> :
> ... Use fans or "swamp coolers" to do more of the work.
Back in 1994 we had the Ford Ecostar EV at the Tour de Sol and there was a line
of solar cells laminated _into_ the windshield at the top. At first glance it
looked like the tinting you sometimes see across the top of windshields. I was
told solar cells ran the heat/cooling electric fan in the dashboard to pull air
from the outside of the car in and push the hot air out through the slightly
opened windows, thus keeping the heat build-up much lower.
I've not seen that sort of thing anywhere else, but one could easily imagine
doing that with a solar panel on the deck below the rear window.
Free energy indeed.
And why limit the idea to electric cars?
--
Mike Bianchi
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Brian,
Tony McCormick painted his Lectric Leopard using a roller and
High Gloss Rustoleum for a total cost of about $21. Check out
http://www.austinev.org/evalbum/84, and look at the bottom of
the entry for his description of the work.
Ralph
Brian Pikkula writes:
>
> Since the majority of our EVs are > 10 years old, the paint on them
> isn't like it used to be. However, I have a hard time justifying
> spending $2k for something that will not propel my EV.
>
> I have some time on my hands while saving up for my next big purchase
> ( a 9" ADC), so I am considering painting the car myself using a
> roller. The kicker is that it costs < $100 to do it (not including
> the random orbit polisher). I'll also be able to bondo the dents,
> too. There are several sites that explain this and show their
> results. Has anyone tried this before? Results?
>
> http://rollyourcar.com/default.aspx
>
> http://carpainting.wetpaint.com/page/Rollering+Interlux+Brightside+Polyurethane+Paint?t=anon
>
> The original thread that introduced the roll on method to the masses:
> (30+ pages)
> http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Number=2331682&page=0&fpart=1&vc=1%3Cbr%20/%3E
>
> Thanks,
> Brian
> http://www.austinev.org/evalbum/960
>
--- End Message ---
--- Begin Message ---
There's a product on the market that gets rolled into a window which
is basically the same thing. It comes with strips of sealing rubber
to place on either side of the unit so that if it happens to rain
while the device is in place your interior doesn't get wet. This
thing is a little muffin fan with solar cells arrayed around it.
Here 'tis:
http://tinyurl.com/3xpsvj
Nothing to do with it myself, but I've thought about getting one for
my car. : ]
Trot, the breezy, fox...
On 6/21/07, M Bianchi <[EMAIL PROTECTED]> wrote:
Lee Hart: wrote ...
> > The A/C in many parts of the country is not a luxury. Here, A/C
> > is a necessity.
> :
> Use a timer to start the A/C a little while before you return to drive
> the car, so it can be far smaller.
> :
> ... Use fans or "swamp coolers" to do more of the work.
Back in 1994 we had the Ford Ecostar EV at the Tour de Sol and there was a line
of solar cells laminated _into_ the windshield at the top. At first glance it
looked like the tinting you sometimes see across the top of windshields. I was
told solar cells ran the heat/cooling electric fan in the dashboard to pull air
from the outside of the car in and push the hot air out through the slightly
opened windows, thus keeping the heat build-up much lower.
I've not seen that sort of thing anywhere else, but one could easily imagine
doing that with a solar panel on the deck below the rear window.
Free energy indeed.
And why limit the idea to electric cars?
--
Mike Bianchi
--
| /\_/\ TrotFox \ Always remember,
| ( o o ) AKA Landon Solomon \ "There is a
| >\_/< [EMAIL PROTECTED] \ third alternative."
--- End Message ---
--- Begin Message ---
Thanks for the way to calculate it! I have always wanted to find that out.
BUT, where do you take the height? From just below the windshield? Just below
the roofline? At what angle do you consider it not to be the front anymore?
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Phil Marino
Sent: Thursday, June 21, 2007 12:12
To: ev@listproc.sjsu.edu
Subject: RE: 55mph - calculating HP
>From: "Dewey, Jody R ATC COMNAVAIRLANT, N422G5G" <[EMAIL PROTECTED]>
>Reply-To: ev@listproc.sjsu.edu
>To: <ev@listproc.sjsu.edu>
>Subject: RE: 55mph
>Date: Thu, 21 Jun 2007 09:06:53 -0400
>
>A lot of people don't have that kind of data though. I don't know the
>Cd of my Nissan or the tire drag coefficient. I do however have the
>ability to use that general calculation.
This reminds me of the story of the guy who was looking for his car keys under
a streetlight. A friend came along and asked him what he was doing there. He
said " I dropped my keys on the next block, but there's no streetlight down
there".
If you don't have the data for your car ( and don't want to try to find it on
the Web) then try this :
Use 0.01 for your tire RR, and use 0.35 for your drag coefficient. For the
frontal area, measure the car's height and width with a tape measure and
multiply them together, then multiply that number by 0.8. That will be a good
approximation. Then you can use the real formula.
You're much better off doing that than using the MOPAR "formula" - it really
makes no sense at all.
Phil Marino
>
>-----Original Message-----
>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
>Behalf Of Phil Marino
>Sent: Thursday, June 21, 2007 8:55
>To: ev@listproc.sjsu.edu
>Subject: RE: 55mph
>
>
>Jody
>
>This doesn't look like a useful formula to me. It might be close at a
>particular speed (similar to a stopped watch being exactly correct twice a
>day), but it would give you huge errors at most speeds.
>
>It makes no account of frontal area, Cd, or tire drag coefficient,
>
>Even worse, its says that the required horsepower it proportional to the
>speed. Because air drag dominates at high speed, and the power it soaks up
>is proportional to the cube of speed, this formula is way off.
>
>For example, it would predict that your car would need twice the power to
>travel at 60 MPH compared to 30 MPH. In most cases, you would need closer
>to six times the power at double the speed.
>
>
>
>If you know the frontal area, Cd, tire RR, and weight, Peter's calculations
>should give you very accurate answers. if you don't know them, take your
>best guess - and use it anyway.
>
>It would still give you much better answers than the MOPAR version.
>
>
>Phil
>
>
>
> >From: "Dewey, Jody R ATC COMNAVAIRLANT, N422G5G" <[EMAIL PROTECTED]>
> >Reply-To: ev@listproc.sjsu.edu
> >To: <ev@listproc.sjsu.edu>
> >Subject: RE: 55mph
> >Date: Thu, 21 Jun 2007 08:29:37 -0400
> >
> >I got this off of a website for MOPARS:
> >
> >Engine horsepower required to sustain MPH on level ground (HPs):
> >
> >
> > HPs =
> > (MPH ÷ 3)
> > + (WEIGHT ÷ 1,000 × MPH ÷ 10)
> >
> >
> >Note: assumes engine HP must be 2 × the HP required at drive wheels.
> >Example:
> >What engine HP is required to sustain 75 MPH in a 3,600 pound vehicle?
> >
> >
> >
> > HPs =
> > 75
> > ÷ 3
> > + (3,600 ÷ 1,000 × 75 ÷ 10)
> > _____________________________
> > 25
> > + (3.6 × 7.5)
> > _______________________________________
> > 52 engine HP
> >
> >
> >-----Original Message-----
> >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
> >Behalf Of Peter Gabrielsson
> >Sent: Thursday, June 21, 2007 2:47
> >To: ev@listproc.sjsu.edu
> >Subject: Re: 55mph
> >
> >The forces you need to overcome are aerodynamic drag plus the rolling
> >resistance. (This presumes level ground and no wind)
> >
> >The power required to overcome aerodynamic drag = 0.5rho*Cd*A*V*V*V
> >where rho = density of air = 1.2 kg/m3, Cd = drag coefficient, A =
> >frontal area of the car in m^2, V = velocity (55mph = 25m/s)
> >
> >For my fiat the numbers would be something like: P = 0.5 * 1.2 * 0.4 *
> >0.6 * 25 * 25 * 25 => 2250W or about 3Hp
> >
> >The power required to overcome rolling resistance = V * Crr * g * m
> >where V = velocity, Crr = coefficient of rolling resistance (0.006 -
> >0.01 for lrr tires), g = gravitational constant (9.81m/s^2), m= mass
> >of car in kg.
> >
> >So for a 1200kg (2500lbs) car with marginally low rolling resistance
> >tires the power needed is 25*0.01*9.81*1200 => 3000W or about 4Hp
> >
> >Total power needed is thus 3+4 = 7Hp at the wheels. In real life you
> >probably want twice as much at the motor. (due to wind, slopes &
> >transmission losses)
> >
> >Someone check for mistakes, it's late ;)
> >
> >
> >
> >
> >On 6/20/07, Rob Hogenmiller <[EMAIL PROTECTED]> wrote:
> > > What is the mathematical formula to determine how much HP I will
> > > need to maintain 55mph.
> > >
> > > For i.e.
> > >
> > > 5,000lbs vehicle x rolling resistance / 10HP= 50mph would eventually
> > > produce given a long enough run.
> > >
> > > (I know that isn't anywhere close to the true formula ust trying to
> > > get an
> > > idea)
> > >
> > > God bless
> > >
> > >
> > >
> > >
> >
> >
> >--
> >www.electric-lemon.com
> >
>
>_________________________________________________________________
>Who's that on the Red Carpet? Play & win glamorous prizes.
>http://club.live.com/red_carpet_reveal.aspx?icid=REDCARPET_hotmailtextlink3
>
_________________________________________________________________
Picture this - share your photos and you could win big!
http://www.GETREALPhotoContest.com?ocid=TXT_TAGHM&loc=us
--- End Message ---
--- Begin Message ---
There is an article in car craft from June that details it step by step.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Ralph Merwin
Sent: Thursday, June 21, 2007 12:25
To: ev@listproc.sjsu.edu
Subject: Re: Slightly OT: Painting your EV for less than $100
Brian,
Tony McCormick painted his Lectric Leopard using a roller and High Gloss
Rustoleum for a total cost of about $21. Check out
http://www.austinev.org/evalbum/84, and look at the bottom of the entry
for his description of the work.
Ralph
Brian Pikkula writes:
>
> Since the majority of our EVs are > 10 years old, the paint on them
> isn't like it used to be. However, I have a hard time justifying
> spending $2k for something that will not propel my EV.
>
> I have some time on my hands while saving up for my next big purchase
> ( a 9" ADC), so I am considering painting the car myself using a
> roller. The kicker is that it costs < $100 to do it (not including
> the random orbit polisher). I'll also be able to bondo the dents,
> too. There are several sites that explain this and show their
> results. Has anyone tried this before? Results?
>
> http://rollyourcar.com/default.aspx
>
> http://carpainting.wetpaint.com/page/Rollering+Interlux+Brightside+Pol
> yurethane+Paint?t=anon
>
> The original thread that introduced the roll on method to the masses:
> (30+ pages)
> http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Number=2331682&;
> page=0&fpart=1&vc=1%3Cbr%20/%3E
>
> Thanks,
> Brian
> http://www.austinev.org/evalbum/960
>
--- End Message ---
--- Begin Message ---
We "hope" to entice the bike into the 7's with this mod, and that is
the very most we could expect.
The 5's are a looooong way away and will require more than twiddling
with the brush timing.
Our present best 60 ft time is 1.167 seconds. An improvement of 0.4
seconds would be a violation of the laws of physics I would imagine. :-)
To get into the 5's (or even into the 6's) we will have to
abandon the DC drive entirely and move up to a high voltage AC drive.
It may be possible to get into the 6's with a DC drive, but it would
probably be the more difficult way to do it.
We are presently "scheming" to get a high-voltage AC drive
for the KillaCycle. I would like to believe at this point that all
the pieces are going to somehow converge to get the AC drive we need
into the bike for next season, but it is all still discussion at this point.
IF we get the AC drive we lust for, and IF we get the
super-duper next generation of A123 cells, and IF we manage to link
all this HP up to the track, then we have a shot at the 6's, and,
perhaps maybe in our dreams, the 5's.
If you don't aim for the bull's eye, you even won't hit the
target. :-)
Bill Dube'
At 03:02 PM 6/20/2007, you wrote:
In a message dated 6/20/2007 8:12:16 AM US Mountain Standard Time,
[EMAIL PROTECTED] writes:
> mbie rises from the dead Siamese8 lives again
> Date:6/20/2007 8:12:16 AM US Mountain Standard Time
> From:[EMAIL PROTECTED]
> Reply-to:ev@listproc.sjsu.edu
> To:ev@listproc.sjsu.edu
> Received from Internet:
>
>
>
>
> --- Loni <[EMAIL PROTECTED]> wrote:
>
> >I look forward to seeing it in action, and I'm
> >curious when someone will be
> >the first to incorporate controller/solenoid
> >modulation of brush timing. I
> >know you and Otmar can do it...Hint hint...
>
> Hey Loni, all
>
> Actually Bill Dube and crew have already set up the
> motors on Killacycle to do this very thing. Like all
> untried things we'll have to wait and see how well it
> works and then improve on it, if it shows promise. I
> feel there is enough data to show it has merit and am
> personally eager to see how it all pans out.
>
I have had brushes moving as I go down track on my 11 incher for 5 years
now.When Bill and John get to try this type of system they will ask
why they had
not done it years ago.It can make my Current Eliminator dragster .3 to .4
seconds quicker in the 1st 60 feet.Bill will need at least this mod
to run the 5.83
at 243mph with the kilacycle that he predicted! Dennis
Berube
--- End Message ---
--- Begin Message ---
From: Marcin Ciosek
> I bought 1900 LiFP cells and the voltage difference between highest
> and lowest value was 7mV!
With the typical open-circuit difference from 0% to 100% SOC being about 0.1v,
this corresponds to roughly 0.007/0.1= 7%. Sounds small, but it's too much to
ignore.
> Assuming you will start from similar point you balancer will do the
> trick as long as zener diodes won't differ too much (usually tolerance
> of of shunt voltage is 5%).
Zener diodes usually have a 5% tolerance, which is too much in this situation.
Also, low voltage zeners have really large variations with current and
temperature. They would be inadequate for per-cell regulation.
Try a zener-equivalent integrated circuit, like a ZL431 or LM138 instead.
> I would add a protection circuit preventing cells from deep
> discharge. If you don't need fancy BMS that would cost (for you
> configuration) 400E this will work fine.
Yes; this is a virtual necessity. Running them down to 2v or so is a one-way
trip!
--
I would not waste my life in friction when it could be turned into momentum. --
Frances Willard
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Frontal area is the the projected area that is occupied by the car
when seen from the front. So you want the widest and tallest point of
the car. the 0.8 factor is to compensate for the fact that your car is
not a perfect square (unless it's a hummer)
Here's a good resource for finding drag and area numbers for cars.
http://www.mayfco.com/tbls.htm
-Peter
On 6/21/07, Dewey, Jody R ATC COMNAVAIRLANT, N422G5G
<[EMAIL PROTECTED]> wrote:
Thanks for the way to calculate it! I have always wanted to find that out.
BUT, where do you take the height? From just below the windshield? Just below
the roofline? At what angle do you consider it not to be the front anymore?
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Phil Marino
Sent: Thursday, June 21, 2007 12:12
To: ev@listproc.sjsu.edu
Subject: RE: 55mph - calculating HP
>From: "Dewey, Jody R ATC COMNAVAIRLANT, N422G5G" <[EMAIL PROTECTED]>
>Reply-To: ev@listproc.sjsu.edu
>To: <ev@listproc.sjsu.edu>
>Subject: RE: 55mph
>Date: Thu, 21 Jun 2007 09:06:53 -0400
>
>A lot of people don't have that kind of data though. I don't know the
>Cd of my Nissan or the tire drag coefficient. I do however have the
>ability to use that general calculation.
This reminds me of the story of the guy who was looking for his car keys under a
streetlight. A friend came along and asked him what he was doing there. He said "
I dropped my keys on the next block, but there's no streetlight down there".
If you don't have the data for your car ( and don't want to try to find it on
the Web) then try this :
Use 0.01 for your tire RR, and use 0.35 for your drag coefficient. For the
frontal area, measure the car's height and width with a tape measure and
multiply them together, then multiply that number by 0.8. That will be a good
approximation. Then you can use the real formula.
You're much better off doing that than using the MOPAR "formula" - it really
makes no sense at all.
Phil Marino
>
>-----Original Message-----
>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
>Behalf Of Phil Marino
>Sent: Thursday, June 21, 2007 8:55
>To: ev@listproc.sjsu.edu
>Subject: RE: 55mph
>
>
>Jody
>
>This doesn't look like a useful formula to me. It might be close at a
>particular speed (similar to a stopped watch being exactly correct twice a
>day), but it would give you huge errors at most speeds.
>
>It makes no account of frontal area, Cd, or tire drag coefficient,
>
>Even worse, its says that the required horsepower it proportional to the
>speed. Because air drag dominates at high speed, and the power it soaks up
>is proportional to the cube of speed, this formula is way off.
>
>For example, it would predict that your car would need twice the power to
>travel at 60 MPH compared to 30 MPH. In most cases, you would need closer
>to six times the power at double the speed.
>
>
>
>If you know the frontal area, Cd, tire RR, and weight, Peter's calculations
>should give you very accurate answers. if you don't know them, take your
>best guess - and use it anyway.
>
>It would still give you much better answers than the MOPAR version.
>
>
>Phil
>
>
>
> >From: "Dewey, Jody R ATC COMNAVAIRLANT, N422G5G" <[EMAIL PROTECTED]>
> >Reply-To: ev@listproc.sjsu.edu
> >To: <ev@listproc.sjsu.edu>
> >Subject: RE: 55mph
> >Date: Thu, 21 Jun 2007 08:29:37 -0400
> >
> >I got this off of a website for MOPARS:
> >
> >Engine horsepower required to sustain MPH on level ground (HPs):
> >
> >
> > HPs =
> > (MPH ÷ 3)
> > + (WEIGHT ÷ 1,000 × MPH ÷ 10)
> >
> >
> >Note: assumes engine HP must be 2 × the HP required at drive wheels.
> >Example:
> >What engine HP is required to sustain 75 MPH in a 3,600 pound vehicle?
> >
> >
> >
> > HPs =
> > 75
> > ÷ 3
> > + (3,600 ÷ 1,000 × 75 ÷ 10)
> > _____________________________
> > 25
> > + (3.6 × 7.5)
> > _______________________________________
> > 52 engine HP
> >
> >
> >-----Original Message-----
> >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
> >Behalf Of Peter Gabrielsson
> >Sent: Thursday, June 21, 2007 2:47
> >To: ev@listproc.sjsu.edu
> >Subject: Re: 55mph
> >
> >The forces you need to overcome are aerodynamic drag plus the rolling
> >resistance. (This presumes level ground and no wind)
> >
> >The power required to overcome aerodynamic drag = 0.5rho*Cd*A*V*V*V
> >where rho = density of air = 1.2 kg/m3, Cd = drag coefficient, A =
> >frontal area of the car in m^2, V = velocity (55mph = 25m/s)
> >
> >For my fiat the numbers would be something like: P = 0.5 * 1.2 * 0.4 *
> >0.6 * 25 * 25 * 25 => 2250W or about 3Hp
> >
> >The power required to overcome rolling resistance = V * Crr * g * m
> >where V = velocity, Crr = coefficient of rolling resistance (0.006 -
> >0.01 for lrr tires), g = gravitational constant (9.81m/s^2), m= mass
> >of car in kg.
> >
> >So for a 1200kg (2500lbs) car with marginally low rolling resistance
> >tires the power needed is 25*0.01*9.81*1200 => 3000W or about 4Hp
> >
> >Total power needed is thus 3+4 = 7Hp at the wheels. In real life you
> >probably want twice as much at the motor. (due to wind, slopes &
> >transmission losses)
> >
> >Someone check for mistakes, it's late ;)
> >
> >
> >
> >
> >On 6/20/07, Rob Hogenmiller <[EMAIL PROTECTED]> wrote:
> > > What is the mathematical formula to determine how much HP I will
> > > need to maintain 55mph.
> > >
> > > For i.e.
> > >
> > > 5,000lbs vehicle x rolling resistance / 10HP= 50mph would eventually
> > > produce given a long enough run.
> > >
> > > (I know that isn't anywhere close to the true formula ust trying to
> > > get an
> > > idea)
> > >
> > > God bless
> > >
> > >
> > >
> > >
> >
> >
> >--
> >www.electric-lemon.com
> >
>
>_________________________________________________________________
>Who's that on the Red Carpet? Play & win glamorous prizes.
>http://club.live.com/red_carpet_reveal.aspx?icid=REDCARPET_hotmailtextlink3
>
_________________________________________________________________
Picture this - share your photos and you could win big!
http://www.GETREALPhotoContest.com?ocid=TXT_TAGHM&loc=us
--
www.electric-lemon.com
--- End Message ---
